feat: multi-LGU tenancy — Phase A (foundation + customer-web)

Backend:
- New tenants table with PSGC-derived code, links to
  cities_municipalities, optional boundary_polygon override, theme
  color, contact info, timezone.
- Adds nullable tenant_id to users / households / drop_off_points /
  dumpsites / partner_stores. Foreign-keyed, indexed.
- Tenant model with deriveCode() helper + effectiveBoundary()
  fallback chain.
- App\Tenancy\Tenancy — process-level current-tenant register with
  withTenant() / withoutScope() helpers for jobs + super-admin.
- App\Tenancy\TenantScope — global Eloquent scope, no-op when no
  tenant is set (so seeders + super-admin reads still work).
- App\Tenancy\HasTenant trait — applied to Household, DropOffPoint,
  Dumpsite, PartnerStore. Auto-fills tenant_id on create from
  Tenancy::current().
- ResolveTenant middleware — reads X-Tenant-Code (or X-Tenant-Id),
  validates tenant exists + active, sets Tenancy::current(). Falls
  back to authenticated user's tenant_id when header missing.
  Registered globally on the api group.
- Login + register now require an active tenant (super-admin
  bypasses). Cross-tenant credential reuse is rejected with a
  403 + clear message.
- super_admin role added to RoleSeeder + users.role enum.
- Public GET /api/v1/tenants/lookup?code= — no auth, returns tenant
  details for the pre-login screen.

Seeders:
- SuperAdminSeeder seeds super@verde.local (tenant_id = null).
- SanPascualTenantSeeder seeds Region IV-A → Batangas → San Pascual
  municipality → sample Poblacion barangay → Tenant row with code
  SAN-PASCUAL-BAT, then backfills every existing tenant-aware row
  (13 users / 2 households / 5 DOPs / 1 dumpsite / 3 stores) so
  the dev environment keeps working end-to-end.
- Wired into DatabaseSeeder so migrate:fresh --seed bootstraps
  cleanly.

Customer-web:
- New /tenant page — text input, calls public lookup, confirms with
  resolved tenant card, stores code + name in cookies (1 year).
  "Pilot users: SAN-PASCUAL-BAT" hint as a clickable shortcut.
- /login + /register now redirect to /tenant?next= when no cookie,
  show a verde "signing in to <LGU>" pill with a Switch link,
  delegate the actual form to client components.
- /api/tenant route — POST sets cookie, DELETE clears.
- apiServer auto-attaches X-Tenant-Code on every API call when the
  cookie is present.
- Tenant cookies are non-httpOnly so the client can echo them; the
  session token stays httpOnly.

Build: 23 routes (added /tenant), 196 backend tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Models/User.php

@@ -20,6 +20,7 @@ class User extends Authenticatable implements MustVerifyEmail
     /** @use HasFactory<\Database\Factories\UserFactory> */
     use HasApiTokens, HasFactory, HasRoles, LogsActivity, Notifiable, SoftDeletes;
 
+    public const ROLE_SUPER_ADMIN = 'super_admin';
     public const ROLE_ADMIN = 'admin';
     public const ROLE_RESIDENT = 'resident';
     public const ROLE_DRIVER = 'driver';
@@ -33,6 +34,7 @@ class User extends Authenticatable implements MustVerifyEmail
 
     protected $fillable = [
         'uuid',
+        'tenant_id',
         'email',
         'phone',
         'password',
@@ -127,6 +129,16 @@ class User extends Authenticatable implements MustVerifyEmail
         return $this->hasOne(StorePartnerProfile::class);
     }
 
+    public function tenant(): \Illuminate\Database\Eloquent\Relations\BelongsTo
+    {
+        return $this->belongsTo(Tenant::class);
+    }
+
+    public function isSuperAdmin(): bool
+    {
+        return $this->role === self::ROLE_SUPER_ADMIN;
+    }
+
     /**
      * Resolve the role-specific profile relation name. Admins have no profile.
      */